This invention generally relates to electric motors. More particularly, this invention relates to an electric motor arrangement within a vehicle drive assembly.
Conventional automotive vehicles have been powered by an internal combustion engine that provides driving torque to one or more sets of wheels to propel the vehicle as desired. Recent trends have been to incorporate other sources of motive power in place of or as a supplement to the internal combustion engine. One such example is an electric hybrid vehicle that utilizes an internal combustion engine power or electric power. One shortcoming of such alternative power arrangements is that the potential benefits are limited by the ability to incorporate such systems onto a vehicle. Designs accommodating alternative power sources are typically heavily dependent on current vehicle component configurations. Limited available space and component designs present serious challenges to effective integration of alternative drive arrangements.
There is a need for alternative arrangements of supplemental or alternative power devices on vehicles so that appropriate control can be accomplished within vehicle packaging constraints. This invention addresses that need and provides a unique arrangement for providing driving torque to one or more wheels of a vehicle
In general terms, this invention is an axle assembly having an electric motor with more than one armature so that more than one motor speed is available to independently provide torque to independently rotatable axle shafts.
One example axle assembly designed according to this invention includes a first axle shaft. A second axle shaft is supported to rotate independently of the first axle shaft. An electric motor includes a stator, a first armature and a second armature. Each armature is associated with one of the axle shafts. A controller controls power to the armatures to independently cause the desired rotation of the first and second axle shafts, respectively.
An electric motor assembly designed according to this invention provides features that are analogous to a mechanical differential gear assembly.